A typical gas spring has a cylindrical casing precharged with a gas, a reciprocable rod protruding from one end connected to a piston disposed within the casing for compressing the gas therein. Gas springs may be employed to aid in the removal of a work piece from a stamping die. The work piece may be lifted out of the forming die after stamping operations have been performed thereon by a low reaction force gas spring mounted in the die. When the dies are open, the rod of the gas spring projects from the die cavity and contacts the work piece. When the dies are closed, the rod is compressed as the force of the stamping operation is exerted on the work piece. As the dies open again, the rod of the gas spring pushes against the work piece thereby lifting the work piece from the die cavity. This helps facilitate removal and transfer of the work piece from one stage of the forming process to the next via robots or mechanical actuators. Depending on the need at each stage of the stamping operation, the gas spring force may be varied by adjusting the depth to which the gas spring is inserted into the die. The longer the stroke of the rod, the higher the force exerted by the gas spring on the work piece.
Gas springs of this type are either clamped or threaded into a die. A gas spring to be clamped into a die normally has a clamp ring groove in the outer circumference of the casing. A gas spring that is to be threaded into a die normally has integral threads formed on the external surface of the casing. The threaded type typically requires a lock nut to secure it in the die. It is difficult to provide clearance in the die for a lock nut that is to be received on the gas spring. If the lock nut is recessed, it is difficult to reach making adjustment and removal of the gas spring more difficult.